diff --git a/src/jsapi-helpers/chain-upgrade.ts b/src/jsapi-helpers/chain-upgrade.ts
index 40d07b1d1..8503cc86a 100644
--- a/src/jsapi-helpers/chain-upgrade.ts
+++ b/src/jsapi-helpers/chain-upgrade.ts
@@ -119,9 +119,7 @@ async function performChainUpgrade(api: ApiPromise, code: string) {
 
   await new Promise<void>(async (resolve, reject) => {
     const unsub = await api.tx.sudo
-      .sudoUncheckedWeight(api.tx.system.setCodeWithoutChecks(`0x${code}`), {
-        refTime: 1,
-      })
+      .sudoUncheckedWeight(api.tx.system.setCodeWithoutChecks(`0x${code}`), 1)
       .signAndSend(alice, (result) => {
         console.log(`Current status is ${result.status}`);
         if (result.status.isInBlock) {